Driving in north London with London’s Metropolitan Police, I was invited to film with them, writes Jamal Osman.

We are heading to an area that is popular with users and dealers of the drug – khat.

Khat is a stimulant; a plant that’s grown in Kenya. East African and Yemeni communities chew the green leaf, especially Somalis. It gives them a buzz and they use it socially in marfashes or khat houses.

Three months ago, the British government made it illegal: a class C drug. The decision brought the UK into line with most western countries.

With more than 40 officers involved, this is a big police operation, the first of its kind.

On the way to the area, Sergeant Matt Howard explained the operation: “What we are looking for are premises that are being used for consumption and possibly the supply of class C drug – khat.

“What we are looking to achieve today is seize any khat we come across and prosecute any offenders that we may encounter.”

Soon after, we arrive at the first raid and the police are here in force. The territorial support group or TSG – they usually deal with riots.

But there was no need to break in as the door was open. Not much is found. The police decide it’s just for personal use. This time the occupant gets away with a warning.

The police move onto the next raid and enter a couple of shops on Church Road in Harlesden that police believe are being used as a place to sell the khat drug.

On the outside of one of them is a halal sign. But what’s on offer inside – khat – is most definitely not.

It’s a restaurant, serving traditional Somali lunch, rice, meat, banana – with a bag of khat available on request. Now it is a crime scene. Police bags full of khat marked “police evidence” are on a table.

Later, a Somali woman is led away, while men look on. The vast majority of the community are in support of the ban.

People like Burhan Jama told me they are behind the police action: “I’m happy if it’s stopping khat because it’s killing my people.”

Before the ban on khat came in, 20 tonnes of the plant would land at Heathrow Airport every day. A bundle of khat used to be sold for £3. Now it’s as much as £30.

Several premises in Harlesden were the focus of the police operation. Three arrests were made, others were warned.

But the real purpose of the police action was to send out a message to khat dealers and users that khat is no longer legal and that the police would enforce the law.

For now, smugglers are finding a way to bring khat into the country, often packaging it as Chinese tea.

But the police say with the support from the Somali community they will reduce khat use.